A Revisited Mechanism of the Graphite-to-Diamond Transition at High Temperature
Document Type
Article
Publication Date
6-12-2020
Publication Title
Matter
Abstract
The graphite-diamond transition, under high-pressure and high-temperature conditions, has been a central subject in physical science. However, its atomistic mechanism remains under debate. Employing large-scale molecular dynamics (MD) simulations, we report a mechanism whereby the diamond nuclei in the graphite matrix propagate in two preferred directions, among which the graphite [120] is about 2.5 times faster than [001]. Consequently, cubic diamond (CD) is the kinetically favorable product, while only a few hexagonal diamonds (HDs) can exist as the twins of CDs. The coherent interface of t-(100)gr//(11-1)cd + [010]gr//[1-10]cd observed in MD simulation was confirmed by our high-resolution transmission electron microscopy experiment. The proposed mechanism not only clarifies the role of HD in graphite-diamond transition but also yields atomistic insight into strengthening synthetic diamond via microstructure engineering.
Keywords
Phase transition; Molecular dynamics simulation; Superhard materials; Crystal growth; Interfaces
Disciplines
Condensed Matter Physics
Language
English
Repository Citation
Zhu, S.,
Yan, X.,
Liu, J.,
Oganov, A. R.,
Zhu, Q.
(2020).
A Revisited Mechanism of the Graphite-to-Diamond Transition at High Temperature.
Matter
http://dx.doi.org/10.1016/j.matt.2020.05.013